Shuttle drive for shoe sewing machines



Nov. 6, 1962 Filed March 31, 1961 T. A. KESTELL ET AL SHUTTLE DRIVE FOR SHOE SEWING MACHINES 2 Sheets-Sheet 1 30 u 28 mllllllllmlllll mlmlllll Inventors Thomas A. Kesi-e ll Gerald 1? Ward By iheir/ltforney Nov. 6, 1962 T. A. KESTELL ETAL 3,062,162

SHUTTLE DRIVE FOR SHOE SEWING MACHINES Filed March 51, 1961 2 Sheets-Sheet 2 United States; Patent SHUTTLE DRIVE FOR SHOE SEWING MACHINES Thomas Aubrey Kestell and Gerald Frank Ward, Leicester, England, assignors to United Shoe Machinery Corporation, Boston, Mass, a corporation of New Jersey Filed Mar. 31, 1961, Ser. No. 99,912 Claims priority, application Great Britain Apr. 27, 1960 9 Claims. (Cl. 112-38) This invention relates to improvements in shuttle driving mechanisms for lock stitch shoe sole sewing machines and, as hereinafter exemplified, the machine is of the type illustrated in United States Letters Patent No. 2,056,670, granted October 6, 1936, upon application of J. Gouldbourn et al.

The machine of the patent is provided with a curved hook needle and other stitch forming and work feeding devices, including a thread measuring mechanism for drawing off from a supply of needle thread an amount suflicient for each stitch, a rotary shuttle having a beak which enters into and carries each loop of needle thread about a bobbin thread case mounted within the shuttle and a take-up operating to draw the needle thread from the shuttle into the work andto set the point of interengagement between the needle and locking thread securely within the work. The shuttle of the patented machine is rotated two complete revolutions in each sewing cycle by a system of gearing and shafts operated from the main sewing shaft of the machine. The system includes a shuttle shaft which is divided and is referred to in the patent as shuttle shaft 45 (FIG. 31), having two offset portions coupled together by means of a drag link connection. The drag link connection is so arranged that the speed of the shuttle is increased momentarily as each loop of needle thread is engaged therewith, so that the shuttle travels at a speed equal to about three rotations in each sewingcycle, thereby allowing more time in each sewing cycle for the-other stitch forming devices to function and the other parts of the machine to operate at an increased speed without affecting the shuttle driving mechanism adversely. The drag link connection also causes a driver engaging the shuttle to slow down after each needle loop reaches a position of greatest extension on the shuttle in readiness to be withdrawn therefrom, so that the shuttle has a tendency to overrun the driver until the throat or root of the shuttle beak engages thedriver. At the opposite side of the driver between the driver and the shuttle heel there is then produced a gap through which the needle loop may pass freely asit is being withdrawn from the shuttle.

While the drag link connection of the prior patent produces adequate results, after substantial wear has taken place there has been a tendency for lost motion to appear in the connections between the two shafts limiting the operating speed of the machine, and the quality of the stitching.

The objects of the present invention are generally to improve a lock stitch shoe outsole sewing machine having suitable driving connections for the driver of a rotary shuttle, to impart to the shuttle a motion, thespeed of which can be accelerated or retarded more readily and in a manner whereby the introduction of undesirable inertia effects may be minimized more effectively and in the extent of acceleration and retardatiton are more conveniently adjusted than heretofore. With the above objects in view there is provided in the illustrated machine a shuttle driving mechanism comprising a rotatable shuttle driver arranged to be driven from the main sewing shaft through the action of an epicyclic gear, having sun, planet carrier and ring memhere one of which members is connected to the main sewing shaft and another of which is connected to the shuttle driver, the machine being provided with motion modifying means acting periodically on the third member of the epicyclic gear to speed up the shuttle driver as each loop of needle thread is engaged by the shuttle. With such mechanism the motion modifying means is more readily controllable for the purposes intended and is less subject to undesirable inertia effects and other undesirable reactions, especially after wear has produced looseness in the operating parts. As hereinafter illustrated, the motion modifying means acts periodically at a readily adjustable time to retard the shuttle driver and to permit the shuttle to overrun the driver, momentarily forming between the driver and the heel of the shuttle a gap through which each loop of needle thread engaging the shuttle may pass freely. Preferably, the motion modifying means comprises an oscillating lever connected to the ring member of the epicyclic gear. In this feature of the invention a releasable connection is provided between the oscillating lever and the ring member of the epicyclic gear, so that in case the thread is jammed between the shuttle and its supporting raceway, no damage to the shuttle driving means occurs. In its specific embodiment the releasable connection takes the form of a spring loaded arm having a projection and notch engagement with the ring member.

These and other features of the invention, as hereinafter described and claimed, will be apparent to those skilled in the art from the following detailed specification and the annexed drawings, in which:

FIG. 1 is a sectional view in left side elevation of portions of actuating mechanism for a shuttle driver in a machine embodying the features of the present invention;

FIG. 2 is a detail view in front elevation of a shuttle and its associated stitch forming and work feeding devices located about the sewing point in the machine containing the shuttle actuating mechanism depicted in FIG. 1;

FIG. 3 is a side sectional plan of some of the portions of the machine shown in FIG. 1;

FIG. 4 is a sectional view on an enlarged scale, the section of which is taken along the line IV-IV of FIG;- 3; and 1 FIG. 5 is a time chart representing the operating rela tionships between certain of the stitch forming devices of the machine.

The illustrated machine is a curved hook needle lock stitch shoe sole sewing machine intended primarily for attaching outsoles to welts of Goodyear welt shoes. Ex cept as hereinafter described, the machine is the same as that disclosed in the Gouldbourn et al. patent, above identified.

Thestitch forming and work feeding devices of the machine include a curved hook needle indicated at 2' (FIG. 2), a shuttle 4, which after engaging a loop of needle thread carries the loop about itself and a locking thread supply case 6 rotatably mounted within the shuttle; a loop spreader or thread lifter 8 for opening up and for presenting each loop of needle thread to the shuttle, a looper 10, a thread finger 12, a work support 14, and a presser foot 16. The shuttle is of the usual construction and is provided with a needle loop engaging beak 18 at one side of a throat and a heel 20 at the other side, within which throat an arcuate arm 21 of a driver 22 is disposed loosely to engage and actuate the shuttle and to enable the needle loop to slide between the driver and the surfaces of the shuttle throat Without damage to the thread or obstruction to its movements about the shuttle.

The shuttle driver 22 is secured to the forward end of a horizontal shaft at 24 and rotation of the driver shaft is derived from a main sewing shaft 26 (see FIG. 3) corresponding to the shaft 15 in the above-identified patent,

3 The sewing shaft 26 has fixed to it a bevel gear 28 (FIG. 3) meshing with a similar gear 30 secured to the lower end of a short vertical shaft 32. The shaft 32 is rotated at the same speed as the main sewing shaft and has mounted on its upper end a spiral gear 34 (similar to the gear 43 of the prior patent). The spiral gear 34 meshes with a corresponding gear 36 which is secured to a driving shaft 38.

In the machine of the prior patent, above identified, the shaft corresponding to the present illustrated shaft 38 acts through a drag link connection to increase and decrease the speed of rotation of the shuttle driver or output shaft 24 with respect to the rotary speed of the sewing shaft 26. If it is necessary to make any change in the extent of relative speed between these shafts it is difficult to maintain the proper timed relationships between the movements of the driver and the shuttle for easy passage of each needle loop through the gap between the driver and the extremities of the shuttle throat. Such diificulty is particularly annoying after wear in the parts of the driving connections for the shuttle driver.

According to the present invention, instead of utilizing a drag link connection, the shaft 38 constitutes the input shaft of an epicyclic gear, the output of which is the shuttle driver shaft 24. The gears 34 and 36 are of such ratio that the input shaft 38 is driven at the same speed as the main sewing shaft 26.

The epicyclic gear comprises three members (FIG. 4), a sun 40, a carrier or spider for three planets 42 and a ring or annulus 44 having internal gear teeth within its periphery. The planet carrier member is indicated at 46 and is secured to the forward end of the input shaft 38. The planet gears 42 mesh with the internal teeth on the ring gear 44- and also with teeth on the sun gear 40, the input shaft 38 and the output or driver shaft 24 being arranged in alinement one with the other. The gear ratio of the parts consisting of the ring gear 44, the planet carrier 46 and the sun gear 40 is such that for every single revolution of the input shaft 38, the output or driver shaft 24- completes three revolutions. To this end the ring gear 44 is formed with sixty teeth on its inner periphery, each planet 42 has fifteen teeth and the sun gear 40 is formed with thirty teeth. The ring gear 44 is rotatably supported on the input shaft 38 by means of ball bearings 48 (FIG. 3) and is formed on its outer periphery with diametrically opposed lugs 50 (FIG. 4) between which there are provided semicircular notches 52. Cooperating with the ring gear 44 motion modifying means is provided for changing the speed of rotation of the shuttle driver 22. This is accomplished by imparting a limited angular movement to the ring gear 44- through connections controlled by the input shaft 38.

The motion modifying means comprises a pair of arms 54, 54 which are suspended on pivots 56 mounted at op-' posite ends of an oscillating lever 58. The lever 58 is secured midway between its ends to a rockshaft 60. The arms 54 act as releasable connections engaging opposite sides of the ring member in the epicyclic gear and each arm has a projection 62 engaging a notch 52 in the ring gear. The arms are normally biased toward each other by means of a pair of interconnecting springs 64 (see also FIG. 3). When excessive force is applied to the ring gear 44, as would occur when the shuttle becomes jammed in its supporting raceway, indicated at 65 in FIG. 2, the projections 62 will be forced out of the notches 52 and the ring gear 44 will be permitted to rotate until any obstruction between the shuttle and its supporting raceway is removed.

It is readily apparent that the means for actuating the shuttle comprises the planet carrier 46 secured to the forward end of the input shaft 38 rotatably connected by gears with a one-to-one ratio to the main sewing shaft and the sun 40 to which the shuttle driver 22 is secured rotating three times for each rotation of the input shaft. The connections thus established cause the ring gear and the shuttle driver to be rotated through the epicyclic gear at a three-to-one ratio, the movement of the ring gear also being controlled by the motion modifying means. Such arrangement is not only readily adjustable and controllable but its adjustment may be kept entirely independent of the critical positions of the shuttle required for successful sewing operations. For instance, in the positions of the shuttle in which its beak 18 engages a loop of needle thread and at which the loop carried by the shuttle is freed from engagement with the shuttle there is no necessity for change so long as the motion modifying means is adjusted to restore the normal driving relationship between the input and output shaft of the epicyclic gear. Such independence of actual motion from timed relationship with critical positions of the shuttle is not possible with a drag link connection, since an adjustment of the length of the drag link necessarily causes a change both in motion and timed relationship between the shuttle and others of the stitch-forming devices.

To actuate the motion modifying connections the lever 52 has a downwardly extending arm to which is pivotally connected an eccentric strap 66. The strap 66 surrounds an eccentric 68 secured to the input shaft 33. Upon rotation of the eccentric there is imparted to the lever 58 a rocking motion to cause the ring gear 44 to shift through a limited angular movement depending upon the eccentricityvof the eccentric. By this arrangement the relative movement between the shuttle and its driver 22 is directly dependent upon the eccentric employed. Thus, a simple and effective construction for controlling this movement is provided.

Assuming that the shuttle driver shaft 24 is rotated in a counterclockwise direction, indicated by the arrow in FIG. 4, then the effect of moving the ring gear 44 in a clockwise direction by the arms 55 as they are actuated by the rotation of the eccentric 68, will cause the epicyclic gear to impart to the shuttle driver shaft a deceleration which assists in the formation and preservation of the gap through which the loop of needle thread is drawn in setting a stitch. In other respects the driving connections for the shuttle are the same as in the prior patent, except that there is also provided on the input shaft 38 a cam 70 (FIGS. 1 and 3) which performs a duty similar to a cam disclosed in the prior patent and identified by the numeral 41, by which a thread lifter 163 of the patent is rocked to spread each loop drawn through the work by the needle for entry of the shuttle beak at the appropriate time in each sewing cycle. As shown in FIG. 1 the cam 70 is operatively connected to parts 72 and 74 corresponding to parts referred to in the prior patent as 231 and 229, respectively.

In operation the output or shuttle driver shaft performs three complete revolutions for each rotation of the input shaft 38 in a single sewing cycle of the machine. Therefore, the shuttle rotates three times for every single rotation of the main sewing shaft 26. The shuttle while it is rotated three times in each sewing cycle is effective to enter a loop of needle thread only during every third rotation and, since the motion modifying means including the epicyclic gear is active only during one rotation in three, there is less wear and opportunity for the parts to vary as a result of lost motion in the mechanism than with the drag link connection which acts during each shuttle rotation in the patented machine.

In the diagram of FIG. 5 the line A-A represents the curve indicating the movements of the thread lifter that is driven by the cam 70 during each complete cycle of machine operation, while the line B-B represents the motion imparted to the shuttle driver shaft 24, the line C-C indicating by reference the modification from a constant speed in the shuttle driver.

From the line A-A it will be seen that in each sewing cycle of the machine while the thread lifter cam performs a complete operation it reaches its maximum position at about 240 in the machine cycle. During this cycle the driver shaft 24 and the shuttle itself rotate three times in succession, each rotation of which is indicated by separate periods at (a), (b), or (c). In the two periods (a) and (b) the shuttle rotates without engaging the thread, but in the period (c) the beak of the shuttle enters and carries the needle thread loop over itself at about the 240 position where the thread lifter movement has reached a maximum. The eccentric 68 is so oriented on the input shaft that it imparts an oscillation to the ring gear 44 with both a maximum and minimum speed of movement above and below the unmodified speed of the shuttle shown by the line C-C. At the point 240 in the machine cycle when the thread lifter movement has reached its maximum the beak of the shuttle enters the loop of needle thread, the shuttle being driven at a speed slightly above that of the driver shaft 24. Thereafter, in the period (c) the etfect of rotating the ring gear 44 in a decelerated sense upon the epicyclic gear is to cause the shuttle driver 22 to slow down, thus tending to create the desired gap between the driver and the heel 30 of the shuttle throat, so that the needle loop may be retracted through the gap freely and without imparting any tension thereto, as illustrated in FIG. 2..

By means of the epicyclic gear and the mechanism, herein illustrated, for modifying the motion of the driver shaft 24 both in an accelerating and in a decelerating sense, it will be appreciated that undesirable erratic movements of the various connections is minimized and detrimental effects of the quality of the stitching is eliminated. It will also be appreciated that a construction of motion modifying mechanism has been provided wherein the timing of the accelerating motion and the amount of acceleration imparted to the shuttle driver may readily be adjusted in order to obtain the best practical results merely by changing the angular position of the eccentric 68 on the shaft 38 or by replacing one eccentric with another of different eccentricity, these changes being possible without affecting each other or the other characteristics of the driving connections for the shuttle.

The nature and scope of the invention having been indicated and a particular embodiment having been described, what is claimed is:

1. A lock stitch shoe sewing machine having a main sewing shaft, stitch forming devices actuated thereby, including a hook needle, a shuttle and a loop spreader for opening up each loop of needle thread and for presenting it to the shuttle, and means for actuating the shuttle, comprising a driver and an epicyclic gear having sun, planet carrier, and ring members, one of the members of which epicyclic gear is connected to the main sewing shaft and another of which is connected to the shuttle driver, in combination with motion modifying means acting periodically on the third member of the epicyclic gear to speed up the shuttle driver as each loop of needle thread is engaged by the shuttle.

2. A lock stitch shoe sewing machine having a main sewing shaft, stitch forming devices actuated thereby, including a hook needle, a shuttle and a loop spreader for opening up each loop of needle thread and for presenting it to the shuttle, means for driving the shuttle comprising a driver, an epicyclic gear having sun, planet carrier and ring members, an input shaft for the epicyclic gear connected for rotation with and at the same speed as the main sewing shaft and connected with one of the members of the epicyclic gear and a shuttle driver shaft connected to another member of the epicyclic gear, in combination with motion modifying means connected with the third member of the epicyclic gear to speed up the shuttle driver as each loop of needle thread is engaged by the shuttle and to retard the speed of the shuttle driver as each loop of needle thread is being drawn from the shuttle.

3. A lock stitch shoe sewing machine, as in claim 2, in which the shuttle driver is provided with a shuttle engaging arm and the motion modifying means acts to retard the shuttle driver and to permit the shuttle to overrun the driver in time to form momentarily between the shuttle engaging arm and the shuttle a gap through which the loop of needle thread carried by the shuttle may pass freely.

4. A lock stitch shoe sewing machine, as in claim 1, in which the motion modifying means comprises an oscillating lever connected to the ring member of the epicyclic gear.

5. A lock stitch shoe sewing machine, as in claim 4, in which a releasable connection is provided between the oscillating lever and the ring member of the epicyclic gear.

6. A lock stitch shoe sewing machine, as in claim 5, in which the releasable connection comprises a spring loaded arm having a projection and notch engagement with the ring member. 7

7. A lock stitch shoe sewing machine, as in claim 5, in which the releasable connection includes two arms pivoted to the oscillating lever and engaged with opposite sides of the ring member and a tension spring connected between the arms.

8. A lock stitch shoe sewing machine, as in claim 1, in which the gears of the epicyclic gear are constructed with a ratio to cause the planet carrier member to be driven one revolution for each complete cycle of operation of the machine and the sun member to be driven three rotations for each complete cycle of operation in the machine while the ring member is restrained from rotation.

9. A lock stitch shoe sewing machine, as in claim 8, in which an eccentric is driven from the main driving shaft and a strap surrounding the eccentric is connected to the lever for oscillating it once for each three rotations of the shuttle.

References Cited in the file of this patent UNITED STATES PATENTS 1,247,536 Inshaw Nov. 20, 1917 2,056,670 Gouldbourn et al. Oct. 6, 1936 2,392,349 Webb Jan. 8, 1946 2,535,774 Armelin Dec. 26, 1950 

